<template>
	<div class="todo-header">
		<input 
			@keyup.enter="handleAddTodo" 
			type="text" 
			placeholder="请输入你的任务名称，按回车键确认" 
		/>
	</div>
</template>

<script>
	//引入nanoid，用于生成唯一标识
	import {nanoid} from 'nanoid'

	export default {
		name: 'Header',
		props:['addTodo'],
		methods: {
			//添加一个todo的回调
			handleAddTodo(event){
				//1.获取用的输入
				let {value} = event.target
				//2.校验数据合法性
				if(!value.trim()) return alert('输入不能为空！')
				//3.将用户的输入包装成一个todo对象
				let todoObj = {id:nanoid(),title:value,done:false}
				//4.将上一步的todoObj“塞入”todos数组（本质是调用了App传入的addTodo）
				this.addTodo(todoObj)
				//5.清空输入框
				event.target.value = ''
			}
		},
	}
</script>

<style scoped>
	/*header*/
	.todo-header input {
		width: 560px;
		height: 28px;
		font-size: 14px;
		border: 1px solid #ccc;
		border-radius: 4px;
		padding: 4px 7px;
	}

	.todo-header input:focus {
		outline: none;
		border-color: rgba(82, 168, 236, 0.8);
		box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(82, 168, 236, 0.6);
	}
</style>